Here is what Bostrom himself says about this analogy:

Perhaps the closest existing analog to a rule set that could govern the actions of a superintelligence operating in the world at large is a legal system. But legal systems have developed through a long process of trial and error, and they regulate relaltively slow-changing human societies. Laws can be revised when necessary. Most importantly, legal systems are administered by judges and juries who generally apply a measure of common sense and human decency to ignore logically possible legal interpretations that are suffciently obviously unwanted and unintended by the lawgivers. It is probably humanly impossible to explicitly formulate a highly complex set of detailed rules, have them apply across a highly diverse set of circumstances, and get it right on the first implemntation.

Superintelligence, p. 139.